Control of defects in pump castings
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We encountered a problem during production: the incoming raw materials appeared to be fine in appearance, but during machining, casting defects such as pores (which were the most common issue) were frequently found. Some problems are quite serious, and by then it’s already too late (production is generally carried out based on orders, with no inventory available and tight delivery deadlines). Since neither the factory nor the foundry has non-destructive testing facilities, is there any other way to check the quality of the castings? (Pre-production control) I would appreciate it if experts could offer some suggestions. Thank you
This post was last edited by 3983596_FPPZ on 2019-3-12 09:00. Casting is a special type of process; unless the shape of the casting is extremely complex, the yield rate is usually low. This is generally due to improper casting techniques or inadequate control during the casting process – factors such as overly wet molding sand, inappropriate gates, runners, and risers, low temperature of the molten iron resulting in poor fluidity, lack of the use of chillers, or pouring at too fast or too slow a pace, among others. To solve this problem, I suggest not purchasing the castings themselves, but rather the roughly processed versions of them. Let the casting manufacturers carry out the rough processing according to the designs; they shall be responsible for any defects in the castings. You should only buy those castings that have been properly rough-processed and are free from defects. This will encourage the casting manufacturers to improve their casting processes and reduce casting defects. Of course, this will result in a slightly higher cost, but compared to the processing time wasted due to casting defects that lead to scrap, as well as the delays in delivery, it is still a very worthwhile option. Otherwise, the pricing will be based on weight, with a large amount of allowance for casting processing; you’ll have to bear all defects in the castings, which is unfair
We can only start by looking at the casting process
Buying roughly processed finished products – that’s a good suggestion; thank you very much. \ud83d\udc4d
It was considered, but the supplier was too poor; procurement focuses only on price and ignores quality. Many people in the factory still think in a traditional way; even though the scale has grown, their mindset remains that of a small workshop, which makes things difficult to manage
There’s nothing to do about it – there’s no unity of thought regarding management reform and innovation, people are too afraid to try, and it’s impossible to implement such changes; all that remains is to invest more money
Such problems are likely a very common phenomenon in the pump and valve manufacturing industry; we usually fix minor defects quickly on our own, while for major defects, we either return the products or ask the supplier to carry out the repairs； The resulting rework costs and delivery delays are inevitable ； It’s impossible to achieve both low costs and high-quality materials when it comes to procurement costs and the quality of incoming goods
Ultimately, it is still a matter of quality control by the procurement subcontractor
This is indeed a troublesome issue; perhaps we should work with a casting manufacturer of better quality
The cost of turning the castings with the lowest purchase price into qualified products is generally the highest